In general, there are two major types of cotton species being cultivated throughout the world, namely Gossypium barbadense and Gossypium hirsutum. These two species are from the genus Gossypium, which comprises at least 40 different cotton species. Gossypium barbadense (sea island cotton) and Gossypium hirsutum (upland cotton) are allotetraploids and are known as New World cotton or “American” cotton. There are striking differences in the physical characteristics of the cotton fibers produced by G. barbadense compared to the cotton fibers produced by G. hirsutum. G. barbadense produces longer cotton fibers than most other cotton species and these fibers are usually called “extra long staple” (ELS) fibers, while those of G. hirsutum are shorter and are called or defined as “upland” fibers. Textiles made of ELS fibers are considered to be of higher quality compared to textiles made with shorter fibers, like those produced by G. hirsutum cotton plants. Thus, textiles produced from ELS cotton fibers are considered more valuable in the textile marketplace.
There have been many studies trying to manipulate cotton genes for fiber quality improvement (U.S. Pat. Nos. 6,169,174; 7,060,874; and 6,995,256), enhanced pesticide toxin production (U.S. Pat. Nos. 6,686,149; 6,140,075; and 6,057,370), and herbicide resistance (U.S. Pat. No. 7,223,906). There have also been studies investigating the genetic polymorphism of various cotton species using PCR-based markers (J. Applied Sci. Res. 3(10)1156-1169, 2007). However, no success has been found in the categorization of cotton cultivars using genetic markers on mature cotton fibers mainly because of the lack of efficient primers to amplify fragmented DNA in mature cotton fibers.
Unfortunately, once cotton fibers are processed and made into yarn and/or fabrics most physical properties have been altered, and there is no reliable method to determine the origin or species of the fibers utilized to produce the yarn or textile(s). Forging clothing or producing knock-off textile items is a serious problem for the textile industry, costing manufacturers and retail stores millions and perhaps billions of dollars annually, in the United States alone. Being able to identify the species of cotton utilized in a textile item would not only be a way to authenticate an item as legitimate, but would also enable the detection of forged or counterfeit textile products.